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Ryunker

Well-known member
Joined
Jun 8, 2018
Messages
288
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141
Location
Madison South Dakota
My Car
1971 Mach1 351C
[url=https://ibb.co/fF5Ono][img]https://preview.ibb.co/dKMw7o/20180526_110612.jpg[/img][/url]
Ok. After 12 years of resting, I got the engine to fire off and run thanks to this forum.

Next problem on deck is fuel  delivery.  

The car will  run (well) until bowl is empty, then it dies

I Can put a sucker on the fuel line and get fuel from the tank thru the line. When I put a vacuum gusge on the inlet side of the fuel pump



it draws like 10 inches of vacuum.

I have like two gallons of fuel in the tank.

Is two gallons in the tank enough Fuel? 

Any suggestion would be great. I am hesitant to add a bunch of fuel, in thed case I must drop the tank or sending unit

 
10" of vac should be more then enough to do the job. u may want to put a gage on the pressure side and see if u are getting 4# of pressure. 2 gal might be light, but like billy said ck for blocked filter. u can also remove fuel tank cap and remove inlet line from pump and blow back into tank to ck for blockage.. make sure u remove the fuel cap !!!!!!

 
I just purposely ran my tank dry to check the resistance reading of the sending unit to fine tune my new VDO fuel gauge set up. After checking with the meter I added 1 1/2 gallons of fuel then used that level to set my custom "empty point" on the fuel interface. I started the engine with this amount of fuel in the tank.

I then went to the gas station and was able to put in an additional 17 3/4 gallons. I was surprised that my tank had a 19 gallon capacity. I could then use this level to set the "full point."

 
Couple of suggestions. Start out by changing all of your rubber lines to new alcohol resistant materials. There is hose back at tank, where the line comes through the inner fender well under the master cylinder, going from fuel line to fuel pump. Also small piece going into carb. Most people add a fuel filter up at the carb and make sure alcohol resistant.

I would do a vacuum check on the fuel pump itself see if it will hold a vacuum. If not the diaphragm is bad. If your oil level is rising then your fuel pump is pumping gas into the oil pan with a bad diaphragm.

You will probably want to eventually pull the fuel tank off and take the float out. There is a filter screen on the pickup tube and they fall apart into the tank. Also might need to clean tank. You can buy just the filter. Also on top of the tank there is a mesh filter where the vapors are pulled from the tank to the canister under the hood to be pulled into the intake and burned off. There is also rubber line there that should be changed to alcohol resistant. You will need new O-rings for both the fuel level float and vapor hook up.

I still pay the extra to get alcohol free fuel but changed the lines never know when I cannot find.

If you buy a new fuel pump take your vacuum pump with you I got bad one out of the box new when I replaced mine.

David

 
Couple of suggestions. Start out by changing all of your rubber lines to new alcohol resistant materials. There is hose back at tank, where the line comes through the inner fender well under the master cylinder, going from fuel line to fuel pump. Also small piece going into carb. Most people add a fuel filter up at the carb and make sure alcohol resistant.

I would do a vacuum check on the fuel pump itself see if it will hold a vacuum. If not the diaphragm is bad. If your oil level is rising then your fuel pump is pumping gas into the oil pan with a bad diaphragm.

You will probably want to eventually pull the fuel tank off and take the float out. There is a filter screen on the pickup tube and they fall apart into the tank. Also might need to clean tank. You can buy just the filter. Also on top of the tank there is a mesh filter where the vapors are pulled from the tank to the canister under the hood to be pulled into the intake and burned off. There is also rubber line there that should be changed to alcohol resistant. You will need new O-rings for both the fuel level float and vapor hook up.

I still pay the extra to get alcohol free fuel but changed the lines never know when I cannot find.

If you buy a new fuel pump take your vacuum pump with you I got bad one out of the box new when I replaced mine.

David
I worked on the car today, found filter thing missing on the fuel sending unit. Ordered new assembly from parts store, will be in tomorrow evening. 

Removed inlet from fuel pump, blew air and carb cleaner thru from fuel sender side with success. Put old fuel sender in a bucket of fuel, filled carb  again still fuel pump won' pump. By the way this is a new pump.

Put a vacuum   guage on the fuel sender tube and found "not a steady vacuum" it bounces from 8" vacuum then to pressure... found that odd, but I don t routinely take reading from a good running car, just broken onews.

I have new rubber as sugested that will go on tomorrow

Thoughts on the vacuum guage bouncing???

 
The eccentric on the camshaft moves the pump arm up and down. It just sucks when the pump arm moves down, so bouncing is normal, just as the fuel will come out in spurts. When the fuel bowl is full, and float needle valve is closed, there will be little, if any suction (vacuum), on the inlet side.

 
Couple of suggestions. Start out by changing all of your rubber lines to new alcohol resistant materials. There is hose back at tank, where the line comes through the inner fender well under the master cylinder, going from fuel line to fuel pump. Also small piece going into carb. Most people add a fuel filter up at the carb and make sure alcohol resistant.

I would do a vacuum check on the fuel pump itself see if it will hold a vacuum. If not the diaphragm is bad. If your oil level is rising then your fuel pump is pumping gas into the oil pan with a bad diaphragm.

You will probably want to eventually pull the fuel tank off and take the float out. There is a filter screen on the pickup tube and they fall apart into the tank. Also might need to clean tank. You can buy just the filter. Also on top of the tank there is a mesh filter where the vapors are pulled from the tank to the canister under the hood to be pulled into the intake and burned off. There is also rubber line there that should be changed to alcohol resistant. You will need new O-rings for both the fuel level float and vapor hook up.

I still pay the extra to get alcohol free fuel but changed the lines never know when I cannot find.

If you buy a new fuel pump take your vacuum pump with you I got bad one out of the box new when I replaced mine.

David
I worked on the car today, found filter thing missing on the fuel sending unit. Ordered new assembly from parts store, will be in tomorrow evening. 

Removed inlet from fuel pump, blew air and carb cleaner thru from fuel sender side with success. Put old fuel sender in a bucket of fuel, filled carb  again still fuel pump won' pump. By the way this is a new pump.

Put a vacuum   guage on the fuel sender tube and found "not a steady vacuum" it bounces from 8" vacuum then to pressure... found that odd, but I don t routinely take reading from a good running car, just broken onews.

I have new rubber as sugested that will go on tomorrow

Thoughts on the vacuum guage bouncing???
All up and running on its own, in short problem was black stuff stuck in the steel fuel lines.

Put in new sending unit, same. Started car with fuel in the bowl, put air pressure in the tank, fuel line disconnected line from carb, started car put blow gun with rag at the gas neck and pressurized  thus black gross Ness came out then good fuel all over. Hooked up fuel line to carb and runs like new

Ttanks to all here

 

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